U.S. Pat. No. 3,541,049 describes the co-use of cyanuric chloride in the preparation of thermoplastic, high-molecular weight polycarbonates.
However, the polycarbonates obtainable by this process for example have no stability towards heat, which leads to discoloration during the thermoplastic processing, and also have a reduced resistance towards the action of light, from which signs of yellowing of the material result.
According to German Patent Specification No. 2,246,106, priority case for U.S. Pat. No. 3,894,991, and German Patent Specification No. 2,346,935, priority case for U.S. Pat. No. 3957 728, the complete incorporation of trihalogeno-s-triazines into polycarbonates containing the s-triazine ring is carried out via primary reactions of the halogen atoms of the triazine ring with appropriate amounts of aromatic dihydroxy compounds and subsequent polycondensation of the products to give high-molecular weight polycarbonates by known polycarbonate preparation processes.